{"product_id":"cdk20-telescope","title":"PlaneWave CDK20 F\/7.7 OTA","description":"\u003cp data-start=\"242\" data-end=\"318\"\u003e\u003cstrong data-start=\"242\" data-end=\"318\"\u003ePlaneWave CDK20 f\/7.77 – 20-Inch Corrected Dall-Kirkham Telescope System\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-start=\"320\" data-end=\"803\"\u003eThe CDK20 f\/7.77 from PlaneWave Instruments stands as a pinnacle of optical precision, engineered for advanced astrophotographers, observatories, and research institutions seeking exceptional image quality and scientific performance. Utilizing PlaneWave’s signature Corrected Dall-Kirkham (CDK) optical system, the CDK20 f\/7.77 eliminates common optical aberrations such as off-axis coma, field curvature, and astigmatism—producing an ultra-flat field across a generous image circle.\u003c\/p\u003e\n\u003cp data-start=\"805\" data-end=\"1123\"\u003eHoused in a lightweight yet structurally rigid carbon fiber optical tube, the CDK20 f\/7.77 ensures long-term mechanical and thermal stability, even in challenging environmental conditions. With fused silica optics and generous back focus, this system is optimized for demanding visual and imaging configurations alike.\u003c\/p\u003e\n\u003chr data-start=\"1125\" data-end=\"1128\"\u003e\n\u003cp data-start=\"1130\" data-end=\"1152\"\u003e\u003cstrong data-start=\"1130\" data-end=\"1152\"\u003eKey Specifications\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-start=\"1154\" data-end=\"1484\"\u003e\u003cstrong data-start=\"1154\" data-end=\"1173\"\u003eOptical Design:\u003c\/strong\u003e Corrected Dall-Kirkham (CDK)\u003cbr data-start=\"1202\" data-end=\"1205\"\u003e\u003cstrong data-start=\"1205\" data-end=\"1224\"\u003eClear Aperture:\u003c\/strong\u003e 508mm (20 in)\u003cbr data-start=\"1238\" data-end=\"1241\"\u003e\u003cstrong data-start=\"1241\" data-end=\"1257\"\u003eFocal Ratio:\u003c\/strong\u003e f\/7.77\u003cbr data-start=\"1264\" data-end=\"1267\"\u003e\u003cstrong data-start=\"1267\" data-end=\"1284\"\u003eFocal Length:\u003c\/strong\u003e 3951mm\u003cbr data-start=\"1291\" data-end=\"1294\"\u003e\u003cstrong data-start=\"1294\" data-end=\"1309\"\u003eBack Focus:\u003c\/strong\u003e 269.49mm from mounting surface\u003cbr data-start=\"1340\" data-end=\"1343\"\u003e\u003cstrong data-start=\"1343\" data-end=\"1360\"\u003eImage Circle:\u003c\/strong\u003e 52mm\u003cbr data-start=\"1365\" data-end=\"1368\"\u003e\u003cstrong data-start=\"1368\" data-end=\"1388\"\u003eMirror Material:\u003c\/strong\u003e Fused silica – low thermal expansion\u003cbr data-start=\"1425\" data-end=\"1428\"\u003e\u003cstrong data-start=\"1428\" data-end=\"1445\"\u003eOTA Material:\u003c\/strong\u003e Carbon fiber – lightweight and rigid\u003c\/p\u003e\n\u003chr data-start=\"1486\" data-end=\"1489\"\u003e\n\u003cp data-start=\"1491\" data-end=\"1521\"\u003e\u003cstrong data-start=\"1491\" data-end=\"1521\"\u003ePerformance \u0026amp; Applications\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-start=\"1523\" data-end=\"1731\"\u003e\u003cstrong data-start=\"1523\" data-end=\"1547\"\u003e- Precision Imaging:\u003c\/strong\u003e\u003cbr data-start=\"1547\" data-end=\"1550\"\u003eThe CDK optical system delivers a perfectly flat, coma-free, and astigmatism-free image field, ideal for capturing sharp, detailed images across large-format CCD and CMOS sensors.\u003c\/p\u003e\n\u003cp data-start=\"1733\" data-end=\"1947\"\u003e\u003cstrong data-start=\"1733\" data-end=\"1776\"\u003e- Thermal Stability for Long Exposures:\u003c\/strong\u003e\u003cbr data-start=\"1776\" data-end=\"1779\"\u003eFused silica optics ensure minimal expansion under temperature changes, reducing focus drift and maintaining sharp star profiles throughout extended imaging sessions.\u003c\/p\u003e\n\u003cp data-start=\"1949\" data-end=\"2156\"\u003e\u003cstrong data-start=\"1949\" data-end=\"1985\"\u003e- Wide Instrument Compatibility:\u003c\/strong\u003e\u003cbr data-start=\"1985\" data-end=\"1988\"\u003eWith 269.49mm of back focus and a 52mm image circle, the CDK20 f\/7.77 easily supports filter wheels, large-format cameras, adaptive optics systems, and spectrographs.\u003c\/p\u003e\n\u003cp data-start=\"2158\" data-end=\"2367\"\u003e\u003cstrong data-start=\"2158\" data-end=\"2191\"\u003e- Research \u0026amp; Educational Use:\u003c\/strong\u003e\u003cbr data-start=\"2191\" data-end=\"2194\"\u003eTrusted by universities, remote observatories, and research facilities, the CDK20 is ideal for scientific photometry, deep-sky surveys, and precise data acquisition tasks.\u003c\/p\u003e","brand":"PlaneWave Instruments","offers":[{"title":"Default Title","offer_id":49937788633376,"sku":"200127Q","price":39000.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0849\/2135\/2480\/files\/planewave-cdk-20-adj2.webp?v=1747437279","url":"https:\/\/firstlightastro.com\/products\/cdk20-telescope","provider":"First Light Astro","version":"1.0","type":"link"}